1. Field of the Invention
The present invention relates to a printing apparatus.
2. Description of Related Art
In a conventional laser printer capable of performing a print operation at a high speed, print data such as document data or image data are received from external equipment such as a host computer or a personal computer to develop the print data into printable bit image data. The developed bit image data are stored into a print image buffer. Then, a laser beam corresponding to bit image data of one raster read out from the print image buffer is emitted from a laser diode to perform a main scanning operation, thereby forming an electrostatic latent image on a photosensitive drum for every dot line. Thereafter, toner is attached to the electrostatic latent image on the photosensitive drum and then transferred onto a recording sheet. The toner on the recording sheet is heated by a fixing heater of a fixing device to fix the toner on the recording sheet, thereby completing a print process. This type of laser print is equipped with an operation panel. The operation panel is provided with setting keys and setting switches for setting various modes on the print process and a print stop key for enforcedly stopping the print process. When the print stop key is manipulated during the print process, the recording sheet under print process remains in the printer, and thus there is a high possibility of a sheet jam occurring. Therefore, in order to prevent a sheet jam, the print process on a current sheet (a page under print process) that is currently being subjected to the print process is completed, and the print sheet is discharged. The print process on subsequent sheets (pages) is enforcedly stopped.
However, usually in this type of laser printer, a user does not manipulate the print stop key to enforcedly stop the print process until the user checks the print content on a recording sheet that has been subjected to the print process and discharged to the outside of the laser printer and finds an error in the print content. Therefore, when the user checks the print content on a printed recording sheet discharged from the laser printer, decides to stop the print process and then manipulates the print stop key, the process of forming an electrostatic latent image on the photosensitive drum is continued to the end for a sheet (one page) under the print process when the print stop key is manipulated. Thus, printing is finished for that sheet even after the print stop key is manipulated. Accordingly, the print process is conducted on the sheet (one page) under print even after the manipulation of the print stop key, and thus the toner is wasted. Particularly when an image having a large print area is printed on a sheet by erroneously inputting incorrect print data, a large amount of toner is attached onto an electrostatic latent image on the photosensitive drum contrary to a user's intention even after the user discovers the error. Thus, a large amount of expensive toner is wasted.